Whatever way you decide to build it the bucket with the tomato plant should sit at least 6 inches off the ground in order to drain any excess
nutrient solution back into reservoir.
If you use 6 inch net pot lid then I would suggest using a low pressure
aeroponic system with just 1 360 degree sprayer to spray the
nutrients onto the roots of the plant for 5 - 10 seconds every 30 - 60 minutes 24 hours a day.
If you use perlite run 1/4 pvc pipe to the top of the bucket. You will drill a hole into the 1/4 pvc that fits a long stem grommet that fits right into the pvc. The grommet should have an opening that can fit a black 1/8 inch feeding tube that will reach from the grommet all the way to 2 inches deep into the perlite below the stem of the tomato plant. The timer settings should be similar as I posted above but can be adjusted as you see fit on how the plant looks.
Both these systems the nutrient water should drain back into the reservoir. If you use low pressure aeroponic system you must cut a piece of screen just like 1 you you have on windows of a house and place it in the drain going back to the reservoir. Aeroponic roots are tremendously long compared to those growing in perlite.
The reservoir should have an air stone that runs for at least 1 hour per day. Oxygenated nutrient water is a 1000 times better than non oxygenated. The ph should be checked on a daily basis until you know it stays at same level Tehran it can be checked at least every 3rd day.
If you need a picture of the grommet and how the tubing looks I will post 1 for you.